above and beyond java 9, 10, 11, 12… - hroug...java-related conferences in croatia 6 conference...

www.hujak.hr 1

Above and Beyond Java 9, 10, 11, 12…

dr. sc. Branko Mihaljević

and

dr. sc. Martin Žagar

HUJAK

A bit of Sentimental Journey

• HUJAK founded in 2011

• Interested in meetups• Well, more drinkups☺

• No one dreamed about organizing conferences ☺

• However, we've got some help… ☺

• … the beginning of a beautiful friendship …

www.hujak.hr 3

JavaCro conferences – 2012-2018

4

Javantura conferences – 2014-2018

www.hujak.hr 5

Java-related Conferences in Croatia

www.hujak.hr 6

Conference Location Date Sessions Tracks Attendees Countries

JavaCro'18 Rovinj 7.-9.5.2018. 47 5 300 15

Javantura v5 Zagreb 17.2.2018. 26 3 300 -

JavaCro'17 Rovinj 10.-12.5.2017. 50 5 280 15

Javantura v4 Zagreb 11.2.2017. 27 3 300 -

HrOUG 2016 Rovinj 18.-22.10.2016. 7 (od 96) 1 (od 9) 450 11

JavaCro'16 Rovinj 18.-20.5.2016. 56 5 260 15

Javantura v3 Zagreb 20.2.2016. 23 - 300 -

JavaCro'15 Rovinj 10.-12.5.2015. 46 5 200 11


JavaCro'14 Poreč 11.-13.5.2014. 50 5 220 11


WebCamp 2013 Zagreb 26.10.2013. 24 - 600 -


JavaCro'13 Tuhelj 3.-5.6.2013. 50 5 200 -


WebCamp 2012 Zagreb 24.11.2012. 24 - -

Java 2012 Tuhelj 29.-30.5.2012. 34 7 170 -


This is our 19th conference!!! ☺#Javantura #JavaCro #HrOUG #proud

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And we are still there☺

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JavaCro and Javanturaconferences in numbers

OK, but let's talk about Java! ☺

• Before we start – some interesting facts:

• Java does not stand for Just Another Vague Acronym ☺

• Invented almost by accident• They were building a new language for set-top box as a "cleaned up" C++ version

• Originally designed for interactive TV and remote handheld devices• Unfortunately, it was ahead of time

• Called Oak at the beginning• Later changed to Java because of copyright issues

• Java was named after a coffee cup slang word• Coffee imported from Indonesian island of Java (Jawa)

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Some other interesting facts ☺

• 0xCAFEBABE in class files is a tribute to the café • Where the Green team from Project Stealth went for coffee every day

• James Gosling, "the Father of Java", joined Amazon Web Services (AWS) team in 2017• After Sun Microsystems, Google (short), and Liquid Robotics

• Joe Palrang, the guy who created the Duke, also worked later on famous cartoon movies• The Simpsons, Shrek, Antz, Flushed Away, and Over the Hedge movies

• JavaScript got its name after Java• But only as a "marketing scam" just to make it more popular

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• #1 Development Platform• Cloud, Microservices, and IoT

• Continued growth of Java for 23 years

• A few Billion Devices run Java

• 10 Million Java Developers in the world• Many have Java Certificates

• OCA, OCP & OCM for Java SE• OCE & OCM for Java EE

• 90% of the Fortune 500 companies use Java

• But not only Java – 50+ JVM languages • including Clojure, Groovy, Scala, JRuby, Jython, Fantom, Kotlin, Ceylon, Xtend, X10, LuaJ,

Golo, Frege, Mirah, Eta… and JavaScript

So, what is… Java?

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Some Terminology

• Java Platform, Standard Edition (Java SE)• Specification of Java language, JVM, and core libraries

• Java Development Kit (JDK)• Tested (binary) implementation of Java SE

• OpenJDK• Open source reference implementation of Java SE

• OpenJDK binary• JDK built from OpenJDK source code

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Current State of Java

• Are you still using Java 8?

• Or you switched to Java 9 / 10?

• Or the latest Java 11?

• What about Java EE?

• Well… let's explain

Java Platform today is:

Stable Secure Free ?However, commonly choose two out of three

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"Moving Java Forward Faster"

• "For Java to remain competitive it must not just continue to move forward — it must move forward faster." Mark Reinhold

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20191995 1998 2001 2004 2007 2010 20222016

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Java EE 6

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Professional Edition

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Java 1.1JDK 1.1

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Java 1JDK 1.0

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Java JDK

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© 2018, HUJAK

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Jakarta EEEclipse

Foundation

OpenJDK (New) Release Model

• New Features included (only) when ready• Not targeted for specific release, but released when feature complete

• Feature release versions released twice a year• Every six months in March and September (from JDK 9)

• Update releases will ship quarterly• in January, April, July, and October

• Long-term support (LTS) feature release every three years• Starting in September of 2018 with JDK 11• Updates will be available for at least three years and quite possibly longer

• Time-Based Release Versioning (JEP 322) openjdk.java.net/jeps/322• Revise the version-string scheme of the Java SE Platform and the JDK• Plans to name it by year and month (JEP 223), i.e. Java 18.3. – abandoned

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http://openjdk.java.net/jeps/322

JDK Version Numbering

• $FEATURE.$INTERIM.$UPDATE.$EMERG• $FEATURE is incremented every six months

• Previously MAJOR

• JDK 10 in March 2018, JDK 11 in September 2018, JDK 12 in March 2019…

• $INTERIM is always zero, reserved for flexibility and future use• Previously MINOR

• $UPDATE is incremented one month after $FEATURE is incremented, and every three months thereafter• Previously SECURITY

• JDK 10.0.1 in April 2018, JDK 10.0.2 in July 2018, JDK 11.0.1 in October 2018…

• $PATCH is emergency patch-release counter• Outside of planned schedule, incremented only when it's necessary to fix a critical issue

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Available JDKs (and Licenses)

• Oracle JDK www.oracle.com/technetwork/java/javase/downloads/ $$$ ?• Oracle Binary Code License (BCL) with FoU (Field of Use) restrictions

• Many OpenJDKs:

• Oracle OpenJDK jdk.java.net/11/• GNU General Public License version 2, with the Classpath Exception (GPLv2cpe) with no restrictions• Security and bug fix updates every (and only for) six months (until next JDK, no overlap)

• Azul's Zulu OpenJDK www.azul.com/downloads/zulu/• Free, from JDK 6 to JDK 11, wide platform support

• AdoptOpenJDK's OpenJDK adoptopenjdk.net• Free, from JDK 8 to JDK 11, without commercial support, wide platform support

• AdoptOpenJDK's OpenJDK based on OpenJ9 adoptopenjdk.net• OpenJ9 is former IBM commercial JVM, now open-sourced to Eclipse foundation

• RedHat's OpenJDK

• SAP's SapMachine OpenJDK

• Other Linux distribution's OpenJDKswww.hujak.hr 17

http://www.oracle.com/technetwork/java/javase/downloads/index.html

http://jdk.java.net/11/

http://www.azul.com/downloads/zulu/

https://adoptopenjdk.net/

https://adoptopenjdk.net/

Demystifying "Free" Java

• $free as in free beer (cost) vs free as in free speech (what can you do)

• For $free use OpenJDK binaries

• For free use OpenJDK with GPLv2+CE license

• Updates refers to code patches – typically $free

• Support means fixing bugs and answering questions – was never $free

www.hujak.hr 18

Oracle's JDK is (not) "free"

• LTS release every 3 years – does not mean 3 years of free updates

• Oracle JDK 11 (and onward) can only be used in production with commercial Java SE subscription• Free JDK 11 (and later) are OpenJDK binaries

• Oracle JDK 8 can be used indefinitely for free• Without any further security patches and bug fixes

• Oracle will lead and contribute to each new JDK (every 6 months)• For all JDK (Feature and LTE releases)

• Will not backport updates, Java community need to do it for LTS release

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Open Sourcing and Converged Binaries

• Goal: No functional difference between OpenJDK and Oracle JDK in JDK 11

• Open sourcing closed-source parts of JDK• Flight recorder

• Mission control

• …

• Removing some closed-source parts• Browser Plugin

• Java Web Start

• JavaFX

• Backwards Compatibility – applications depending on Java SE should work

www.hujak.hr 20

Converged Binaries

Up to JDK 10

Oracle JDK

OpenJDK

Java SE

JDK 11 and later

OpenJDK & Oracle JDK

Java SE

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• What/where to download Java today?• OpenJDK

• Oracle JDK

• Some other OpenJDK?• Zulu (Azul Systems)

or AdoptOpenJDK

• Currently available downloads of Oracle's JDK:• Java SE 11.0.1

• Java SE 8u191

www.hujak.hr 22

Java Download

What about www.java.com?

• Well… we don't know?!?

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(Long Term) Support

• Long Term Support (LTS) for all releases is not practical

• One Long Term Support release every three years• Starting with JDK 11 (September 2018), then JDK 17 (September 2021), then JDK 23…

• For Oracle's commercial customers updates available for at least three years or longer

• JDK 9 – supported until March 2018 (release of JDK 10)

• JDK 10 – supported until September 2018 (release of JDK 11)

• JDK 11 (September 2018) – supported until March 2019 (JDK 12)

• JDK 12 (March 2019) …

• JDK change every six months?

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Public Updates and Support – from 7 till 17

Java SE

VersionPublic Release Versions Oracle Support

Commercial / Personal User

End of Public Updates

Oracle's Premier /

Extended Support

7 July 2011 Long Term Support (LTS) - July 2019 / July 2022

8 March 2014 8u191 – October 2018 Long Term Support (LTS) January 2019 / December 2020 March 2022 / March 2025

9 September 2017 9.0.4+11 – January 2018 Short Term Support March 2018 March 2018 / NA

10 March 2018

10.0.0

10.0.1 – April 2018

10.0.2 – July 2018

Short Term Support September 2018 September 2018 / NA

11 September 2018

11.0.0 LTS

11.0.1 – October 2018

11.0.2 – January 2019

Long Term Support (LTS) *September 2023 /

September 2026

12 March 2019 - Short Term Support - -

13 September 2019 - Short Term Support - -


15 September 2020 - Short Term Support - -


17 September 2021 - Long Term Support (LTS) - -

www.hujak.hr 25* https://blogs.oracle.com/java-platform-group/oracle-jdk-releases-for-java-11-and-later

https://blogs.oracle.com/java-platform-group/oracle-jdk-releases-for-java-11-and-later

JDK 9/10 – old news?

• A lot of significant changes

• Java Platform Module System (JPMS)• All core Java libraries become modules (JEP 220)• 97 modules: 28 Java SE, 8 JavaFX, 59 JDK, 2 Oracle…• Most internal APIs encapsulated (JEP 260)

• Deprecated APIs removed• 1 package, many classes and methods

• Redundant features eliminated• Numerous deprecated GC options, jhat tool, TI hprof agent…

• Many command line changes• Removed 200+ -XX flags

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JDK 10

• JDK 10 was available since March 20th, 2018• JSR 383 – Oracle, IBM, Red

Hat, SAP, Azul…• openjdk.java.net/projects/jdk

/10/

• 109 new features and APIs

• JEPs included• 286: Local-Variable Type Inference• 296: Consolidate the JDK Forest into a Single Repository• 304: Garbage-Collector Interface• 307: Parallel Full GC for G1• 310: Application Class-Data Sharing• 312: Thread-Local Handshakes• 313: Remove the Native-Header Generation Tool (javah)• 314: Additional Unicode Language-Tag Extensions• 316: Heap Allocation on Alternative Memory Devices• 317: Experimental Java-Based JIT Compiler• 319: Root Certificates• 322: Time-Based Release Versioning

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http://openjdk.java.net/projects/jdk/10/

Local Variable Type Inference

• JEP 286 http://openjdk.java.net/jeps/286• Extending type inference to declarations of local variables and initializers

• Reducing the ceremony associated with writing Java• Maintaining the commitment to static type safety

• Examples:var list = new ArrayList<String>(); // infers ArrayList<String>var stream = list.stream(); // infers Stream<String>var m = new HashMap <String, List<BigDecimal>>();

• Guidelines:• Restricted to: local variables with initializers, indexes in the enhanced for-loop, locals

declared in a traditional for-loop• Not available for: method parameters, constructor parameters, method return types,

fields, catch formals or any other kind of variable declaration

• Don't blame language features for making developers write sh**y code – Simon Maple

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Garbage Collector Interface

• JEP 304 http://openjdk.java.net/jeps/304

• Introducing a clean GC interface to improve source code isolation of different GCs• Better modularity for HotSpot internal GC code• Simpler to add a new GC to HotSpot without perturbing the current code base• Make it easier to exclude a GC from a JDK build

• Bits and pieces of GC source files scattered all over the HotSpot sources• Becomes an issue when implementing a new garbage collector

• BTW, some of our own experimenting with GCs (Parallel, CMS, G1…)• Comparison of Garbage Collectors in Java Programming Language at MIPRO 2018

www.hujak.hr 29


Parallel Full GC for G1


• Improving G1 worst-case latencies by making the full GC parallel• G1 GC (default GC since JDK 9) designed to avoid full collections• When concurrent collections can't reclaim memory fast enough – fall back full GC • Previous G1 implementation was using single threaded algorithm

• Previous default was parallel collector (had parallel full GC)

• To minimize the impact for users experiencing full GCs, the G1 full GC was made parallel as well• Intends to parallelize the mark-sweep-compact algorithm

• Use the same number of threads as the Young and Mixed collections do

• Number of threads controlled by the -XX:ParallelGCThreads option• It will also affect the number of threads used for Young and Mixed collections

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Handshakes, heap allocation, and Unicode

• Thread-Local Handshakes • JEP 312 openjdk.java.net/jeps/312

• Introduces how to execute a callback on threads, without performing a global VM safepoint

• It is both possible and cheap to stop individual threads and not just all threads or none

• Heap Allocation on Alternative Memory Devices• JEP 316 openjdk.java.net/jeps/316

• Allocate Java object heap on an alternative memory device (e.g. NV-DIMM)

• Additional Unicode Language-Tag Extensions• JEP 314 openjdk.java.net/jeps/314

• Enhance java.util.Locale and related APIs to implement additional Unicode extensions of language tag syntax (BCP 47)

www.hujak.hr 31




Some Housekeeping

• Experimental Java-Based JIT Compiler (Graal)• JEP 317 openjdk.java.net/jeps/317• Performance ☺ – hotspots compiled to native• Enable Graal (Java-based JIT compiler) to be used as experimental JIT compiler

-XX:+UnlockExperimentalVMOptions -XX:+UseJVMCICompiler

• Root Certificates• JEP 319 openjdk.java.net/jeps/319• Provide a default set of root Certification Authority (CA) certificates in JDK• Open source the root certificates in Oracle’s Java SE Root CA program

• Consolidate the JDK Forest into a Single Repository• JEP 296 openjdk.java.net/jeps/296• Combine the various repositories of JDK forest into a single repository• Simplify and streamline development (FX not included)

• Remove the Native-Header Generation Tool (javah) • JEP 313 openjdk.java.net/jeps/313• Remove the javah tool from the JDK, superseded by superior functionality in javac

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New APIs

• 73 additional new APIs• copyOf(Collection) in List, Set and Map• Optional.orElseThrow() – get or throw• toUnmodifiableList/Map/Set

• Some APIs removed• Based on Java SE 10 (18.3) ( JSR 383) Proposed Final Draft Specification

cr.openjdk.java.net/~iris/se/10/pfd/java-se-10-pfd-spec-01/#APIs-removed• Optional annotation element forRemoval=true to previously deprecated API

elements• Remove deprecated methods Runtime.getLocalized{Input,Output}Stream• Remove deprecated pre-1.2 SecurityManager methods and fields• De-deprecate XMLInputFactory.newFactory()

www.hujak.hr 33

http://cr.openjdk.java.net/~iris/se/10/pfd/java-se-10-pfd-spec-01/#APIs-removed

JDK 11

• JDK 11 is in General Availability• JSR 384 – Oracle, IBM, Red Hat,

SAP, Azul…

• openjdk.java.net/projects/jdk/11/

• 90 new features in JDK 11• Post by Simon Ritter

• https://www.azul.com/90-new-features-and-apis-in-jdk-11/

• Less Developer Visible Features

• What is inside?

• JEPs included• 181: Nest-Based Access Control• 309: Dynamic Class-File Constants• 315: Improve Aarch64 Intrinsics• 318: Epsilon: A No-Op Garbage Collector• 320: Remove the Java EE and CORBA Modules• 321: HTTP Client (Standard)• 323: Local-Variable Syntax for Lambda Parameters• 324: Key Agreement with Curve25519 and Curve448• 327: Unicode 10• 328: Flight Recorder• 329: ChaCha20 and Poly1305 Cryptographic Algorithms• 330: Launch Single-File Source-Code Programs• 331: Low-Overhead Heap Profiling• 332: Transport Layer Security (TLS) 1.3• 333: ZGC: A Scalable Low-Latency Garbage Collector • 335: Deprecate the Nashorn JavaScript Engine• 336: Deprecate the Pack200 Tools and APIwww.hujak.hr 34


https://www.azul.com/90-new-features-and-apis-in-jdk-11/

Local-Variable Syntax for LambdaParameters


• Extending Local-Variable Type Inference (JEP 286) – but now for Lambda expressions• Uniformity of local variables and lambdas

• Allow var when declaring formal parameters of implicitly typed lambda expressions(var x, var y) -> x.process(y)

• For all formal parameters or none of them(var x, y) -> x.process(y) // Can't mix 'var' and 'no var' in implicitly typed lambdas

• Explicitly typed lambda expressions continue to use data types for all their formal parameters(var x, int y) -> x.process(y) // Can't mix 'var' and data types in explicitly typed lambdas

• Not compromising the brevity of the shorthand syntaxvar x -> x.foo() // is not allowed

www.hujak.hr 35


Local-Variable Syntax for LambdaParameters – Example

• Example (by Simon Ritter):list.stream()

.map((var s) -> s.toLowerCase())

.collect(Collectors.toList());

• Lambda expressions already have type inference so use of var is not necessary:list.stream()

.map(s -> s.toLowerCase())


• When adding an annotation to Lambda parameter you have to use a (explicit) type, and we can use var insteadlist.stream()

.map((@Notnull var s) -> s.toLowerCase())


• Also causes changes to the Java Language Specification (JLS) :• Description of the var special identifier, Lambda parameters, Runtime evaluation of Lambda

expressions, and Lambda syntax

www.hujak.hr 36

Launch Single-File Source-Code Programs


• Run a program supplied as a single file of Java source code• Reduce the ‘ceremony’ of running trivial applications• Including usage from within a script by means of "shebang" files and related techniques

• Example:java HelloWorld.java

• Parameters:• After the name of the source file are passed as parameters when executing application• Before the name of the source file are passed as parameters to launcher after code has been compiled

• Example:java -classpath /home/foo/java Hello.java Bonjour

• is equivalent to:javac -classpath /home/foo/java Hello.javajava -classpath /home/foo/java Hello Bonjour

www.hujak.hr 37


Launch Single-File Source-Code Programs –Shebang files support

• Usage from within a script by means of "shebang" files and related techniques

• "Shebang" file – small utility single-file program starting with #! #!interpreter [optional-arg]• On Unix-derived systems (Linux, macOS)• Allows a script or source code to be placed in any executable file (whose first line begins with #!),

specifying name of a program to "execute" the contents of the file

• Reducing the need to even mention the Java launcher on the command line

• Simply included on the first line of the source file

• Example:#!/usr/bin/java --source 11

public class HelloWorld {...

• However, necessary to specify the –source flag with the version of Java

www.hujak.hr 38

HTTP Client (Standard)


• New API in JDK 9 to provide support for the HTTP Client protocol (JEP 110) with HTTP/2 support• Since JDK 9 introduced the Java Platform Module System (JPMS), it was included as an

incubator module• Later updated in JDK 10

• HTTP Client API is now part of the Java SE 11 standard

• New module and package java.net.http

• Main types:• HttpClient, HttpRequest, HttpResponse, WebSocket

• API can be used synchronously or asynchronously• Asynchronous mode makes use of CompletableFutures and CompletionStages

www.hujak.hr 39


HTTP Client (Standard) – Some details

• While incubating in JDK 9 and JDK 10, implementation was almost completely rewritten

• The implementation is now completely asynchronous• Previous HTTP/1.1 implementation was blocking

• Provides non-blocking request and response semantics through CompletableFutures• Which can be chained to trigger dependent actions

• Back-pressure and flow-control of request and response bodies is provided for via the Platform's reactive-streams support in the java.util.concurrent.Flow API

• Use of the RX Flow concept has been pushed down into the implementation• Eliminated many of the original custom concepts needed to support HTTP/2

• The flow of data can now be more easily traced• From user-level request publishers and response subscribers down to the underlying socket• Significantly reduces the number of concepts and complexity in the code• Maximizes the possibility of reuse between HTTP/1.1 and HTTP/2

www.hujak.hr 40

Remove Java EE and CORBA Modules


• Remove Java EE and CORBA modules from Java SE Platform and JDK• Modules deprecated in Java SE 9 with intent to remove them in a future

• Java SE 6 included a full Web Services stack (originally developed for the Java EE Platform):• JAX-WS (Java API for XML-Based Web Services)

• JAXB (Java Architecture for XML Binding)

• JAF (the JavaBeans Activation Framework)

• Common Annotations

www.hujak.hr 41


Remove Java EE and CORBA Modules #2

• JEP 320 http://openjdk.java.net/jeps/320 cont'd

• At the time of inclusion, versions in Java SE and Java EE were identical• Except one package in Common Annotations

• Over time, versions in Java EE evolved (difficulties for versions in Java SE):• Technologies gained features that were not relevant to Java SE (like Common Annotations

package for data sources in a Java EE container)• Maintenance problematic due to having to sync the Java SE (in OpenJDK) with the Java EE

versions (in upstream repositories)• Possible to obtain standalone versions of the technologies from the upstream projects and

deploy them – unfortunately, it was not widely used in practice

• With JPMS we can divide the monolithic rt.jar file into multiple modules• Additionally possible to create a Java runtime only with modules you need – reduces size

www.hujak.hr 42


Remove Java EE and CORBA Modules

• Java.se.ee meta-module includes six modules that are no longer part of JDK:• corba

• transaction

• activation

• xml.bind

• xml.ws

• xml.ws.annotation

• If you still use APIs from these modules in your code, you supply them as a separate module or library

• It seems that the java.xml modules, which are part of the JAX-WS, SOAP-based web services support are the ones that are causing most problems

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Flight Recorder

• JEP 328 http://openjdk.java.net/jeps/328• Low-overhead data collection framework for troubleshooting Java applications

on JVM• Prior to JDK 11 it was a commercial feature in Oracle JDK binary• Oracle eliminated functional differences between Oracle JDK and OpenJDK and it

was contributed to the OpenJDK• Goals:

• Provides APIs for producing and consuming data as events• Provides a buffer mechanism and a binary data format• Allows the configuration and filtering of events• Provides events for the OS, the HotSpot JVM, and the JDK libraries

• Two new modules : jdk.jfr and jdk.management.jfr

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New API in JDK 11

• A lot of the new APIs in JDK 11 • For a complete list of API changes, comparison by Gunnar Morling

• https://gunnarmorling.github.io/jdk-api-diff/jdk10-jdk11-api-diff.html

• 6 new classes and 8 methods in java.security modules• Specific to the changes of JEP 324 and JEP 329

• New methods• In 8 slides

www.hujak.hr 45

https://gunnarmorling.github.io/jdk-api-diff/jdk10-jdk11-api-diff.html

New Methods in JDK 11

• New methods – java.io:

• java.io.ByteArrayOutputStream• void writeBytes(byte[]) – write all the bytes of the parameter to the output stream

• java.io.FileReader• Two new constructors that allow a Charset to be specified

• java.io.FileWriter• Four new constructors that allow a Charset to be specified

• java.io.InputStream• io.InputStream nullInputStream() – returns an InputStream that reads no bytes

• java.io.OutputStream• io.OutputStream nullOutputStream() – like dev/null

• java.io.Reader• io.Reader nullReader()

• java.io.Writer• io.Writer nullWriter()

www.hujak.hr 46

New Methods in JDK 11 #2

• New methods – java.lang:• java.lang.Character

• String toString(int) – overloaded form takes an int instead of a char as Unicode code point

• java.lang.CharSequence• int compare(CharSequence , CharSequence) – compares two CharSequence instances

lexicographically • Negative, zero, or positive if 1st CharSequence is lexicographically less than, equal to, or

greater than 2nd CharSequence, respectively

• java.lang.ref.Reference• lang.Object clone() – confusing, maybe for the future

• java.lang.System and java.lang.Runtime• No new methods, runFinalizersOnExit() method removed

• java.lang.Thread• No additional methods, destroy() and stop(Throwable) methods removed

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• New methods – java.lang:• java.lang.String

• boolean isBlank() – returns true if string is empty or contains only white space codepoints• Stream lines() – returns a stream of lines extracted from this string, separated by line

terminators• String repeat(int) – returns a string whose value is the concatenation of this string repeated

count times• String strip() – returns a string whose value is this string, with all leading and trailing

whitespace removed (different whitespace treatment than in trim())• String stripLeading() – returns a string whose value is this string, with all leading whitespace

removed• String stripTrainling() – returns a string whose value is this string, with all trailing whitespace

removed

• java.lang.StringBuffer and java.lang.StringBuilder• New compareTo() method that takes a StringBuffer/StringBuilder and returns an int

(lexographical comparison same as for CharSequence)www.hujak.hr 48


• New methods – java.nio:

• java.nio.ByteBuffer, CharBuffer, DoubleBuffer, FloatBuffer, LongBuffer, ShortBuffer• mismatch() - finds and returns the relative index of the first mismatch between this buffer and a

given buffer

• java.nio.channels.SelectionKey• int interestOpsAnd(int) – atomically sets this key’s interest set to the bitwise intersection ("and") of

the existing interest set and the given value• int interestOpsOr(int) – atomically sets this key’s interest set to the bitwise union ("or") of the

existing interest set and the given value

• java.nio.channels.Selector• int select(java.util.function.Consumer, long) – selects and performs an action on the keys whose

corresponding channels are ready for I/O operations with timeout• int select(java.util.function.Consumer) – as above, except without the timeout• int selectNow(java.util.function.Consumer) – as above, except it is non-blocking

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• New methods – java.nio (cont'd):• java.nio.file.Files

• String readString(Path): Reads all content from a file into a string, decoding from bytes to characters using the UTF-8 charset.

• String readString(Path, Charset): As above, except decoding from bytes to characters using the specified Charset.

• Path writeString(Path, CharSequence, java.nio.file. OpenOption[]:Write a CharSequence to a file. Characters are encoded into bytes using the UTF-8 charset.

• Path writeString(Path, CharSequence, java.nio.file. Charset, OpenOption[]: As above, except Characters are encoded into bytes using the specified Charset.

• java.nio.file.Path• Path of(String, String[]): Returns a Path by converting a path string, or a sequence of strings

that when joined form a path string.• Path of(net.URI): Returns a Path by converting a URI

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• New methods – java.util:

• java.util.concurrent.PriorityBlockingQueue and java.util.PriorityQueue• void forEach(java.util.function.Consumer): Performs the given action for each element of the Iterable until

all elements have been processed or the action throws an exception.• boolean removeAll(java.util.Collection): Removes all of this collection’s elements that are also contained in

the specified collection (optional operation).• boolean removeIf(java.util.function.Predicate): Removes all of the elements of this collection that satisfy

the given predicate.• boolean retainAll(java.util.Collection): Retains only the elements in this collection that are contained in the

specified collection (optional operation).

• java.util.concurrent.TimeUnit• long convert(java.time.Duration): Converts the given time duration to this unit.

• java.util.function.Predicate• Predicate not(Predicate). Returns a predicate that is the negation of the supplied predicate• Example: convert lines.stream().filter(s -> !s.isBlank()) to

lines.stream().filter(Predicate.not(String::isBlank))with static import lines.stream().filter(not(String::isBlank))

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• New methods – java.util:

• java.util.Optional, OptionalInt, OptionalDouble, OptionalLong• boolean isEmpty():If a value is not present, it returns true, otherwise it is false.

• java.util.regex.Pattern• Predicate asMatchPredicate(): I think this could be a hidden gem in the new JDK 11 APIs. It creates a predicate that

tests if this pattern matches a given input string.

• java.util.zip.Deflater• int deflate(ByteBuffer): Compresses the input data and fills the specified buffer with compressed data.• int deflate(ByteBuffer, int): Compresses the input data and fills the specified buffer with compressed data. Returns the

actual number of bytes of data compressed.• void setDictionary(ByteBuffer): Sets the preset dictionary for compression to the bytes in the given buffer. This is an

overloaded form of an existing method that can now accept a ByteBuffer, rather than a byte array.• void setInput(ByteBuffer): Sets input data for compression. Also an overloaded form of an existing method.

• java.util.zip.Inflater• int inflate(ByteBuffer): Uncompresses bytes into the specified buffer. Returns the actual number of bytes

uncompressed.• void setDictionary(ByteBuffer): Sets the preset dictionary to the bytes in the given buffer. An overloaded form of an

existing method.• void setInput(ByteBuffer): Sets input data for decompression. An overloaded form of an existing method.

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• New methods – javax.print, javax.swing, and jdk.jshell:

• javax.print.attribute.standard.DialogOwner• This is a new class in JDK 11 and is an attribute class used to support requesting a print or page setup

dialog be kept displayed on top of all windows or some specific window.

• javax.swing.DefaultComboBoxModel, DefaultListModel• void addAll(Collection): Adds all of the elements present in the collection.• void addAll(int, Collection): Adds all of the elements present in the collection, starting from the

specified index.

• javax.swing.ListSelectionModel• int[] getSelectedIndices(): Returns an array of all of the selected indices in the selection model in

increasing order.• int getSelectedItemsCount(): Returns the number of selected items.

• jdk.jshell.EvalException• jshell.JShellException getCause(): Returns the wrapped cause of the throwable in the executing client

represented by this EvalException or null if the cause is non-existent or unknown.

www.hujak.hr 53

Nest-Based Access Control


• Java supports nesting of classes through inner classes• Logically, the inner class is part of the same code entity as the outer class• However, it is compiled as a separate class• Synthetic bridge method is created by the compiler to provide access to the private field of the outer class

• Introducing the concept of nests• Two members of the same nest (e.g., outer and inner class) are nestmates• NestHost and NestMembers attributes are defined for the class file format• Useful also for other languages compiled to bytecodes that support nested classes

• This feature introduces three new methods to java.lang.Class:• Class getNestHost()• Class[] getNestMembers()• boolean isNestmateOf(Class)

• Changes to JVMS in Access Control

www.hujak.hr 54


Dynamic Class-File Constants

• JEP 309 http://openjdk.java.net/jeps/309• Extension of the class-file format to support a new constant-pool form

CONSTANT_Dynamic (or "condy")• Idea of a dynamic constant seems to be an oxymoron• However, similar to a final value in Java • Like invokedynamic but for class-file constants

• Constant-pool value uses a bootstrap method to determine the value at runtime, not at compile-time (unlike the other constants)• Value is therefore "dynamic", but (since its value is only set once) it is also "constant"

• Simplifications primarily aimed at development of new JVM languages and compilers that generate bytecodes

• Introduces java.lang.invoke.ConstantBootstraps class with 9 new bootstrap methods for dynamically computed constants

• Changes to the JVMS in usage of invokespecial bytecode and Constant Poolwww.hujak.hr 55


Cryptographic-related changes

• Key Agreement with Curve25519 and Curve448• JEP 324 http://openjdk.java.net/jeps/324

• Replacing existing elliptic curve Diffie-Hellman (ECDH) scheme with Curve25519 and Curve448

• Key agreement scheme defined by RFC-7748

• ChaCha20 and Poly1305 Cryptographic Algorithms• JEP 329 http://openjdk.java.net/jeps/329

• Implementation of ChaCha20 and ChaCha20-Poly1305 ciphers as specified in RFC 7539, replacing the older insecure RC4 stream cipher

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Garbage Collection

• ZGC A Scalable, Low Latency Garbage Collector• JEP 333 http://openjdk.java.net/jeps/333• New experimental garbage collector designed for applications that require a large

(multi-gigabyte) heap and low-latency• Uses a single generation heap and performs most of GC concurrently with the

application• Read-barrier that intercepts each read to an object from the application and ensures

that the reference returned is correct• Eliminates issue of being able to relocate objects concurrently while application

threads are running• Region-based (like G1), NUMA aware and compacting• Not intended as a general-purpose collector

www.hujak.hr 57


Garbage Collection #2

• Epsilon: A No-Op Garbage Collector• JEP 318 http://openjdk.java.net/jeps/318 (by Red Hat)

• Epsilon Garbage Collector handles memory allocation but does not implement any actual memory reclamation mechanism of space occupied by unreferenced objects

• Designed to test and compare GC performance with and without GC

• For very short-lived tasks (like serverless functions in the cloud) which do not exceed the memory allocated to the heap

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Other JEPs in JDK 11

• Unicode 10• JEP 327 http://openjdk.java.net/jeps/327

• Support for Unicode 10.0 standard with 8,518 new symbols

• Includes more Emojis, Bitcoin symbol, Nüshu character set, as well as Soyombo and Zanabazar Square

• Improve Aarch64 Intrinsics• JEP 315 http://openjdk.java.net/jeps/315 (by Red Hat)

• Take advantage of specialized instructions in Arm64 instruction set

• Improves performance of sin(), cos() and log() methods of the java.lang.Math class

www.hujak.hr 59



Housekeeping continues

• Removals in JDK 11• Applets, Browser Plugin, Web Start, Java FX

• Deprecate the Nashorn Scripting Engine• JEP 335 http://openjdk.java.net/jeps/335• Deprecates Nashorn introduced in JDK 8 as a replacement of Rhino Javascript engine• Suggests using Graal VM as replacement

• How that will work has not been evaluated

• Completely remove Nashorn with associated APIs and jjs tool in the future

• Deprecate the Pack200 Tools and APIs• JEP 336 http://openjdk.java.net/jeps/336• With JPMS in JDK 9, Pack200 a compression scheme for JARs is no longer used• Deprecates pack200 and unpack200 tools, and Pack200 API in java.util.jar, and may be

removed in a future

www.hujak.hr 60



Others

• Low-overhead Heap Profiling• JEP 331 http://openjdk.java.net/jeps/331 (by Google)• Provides a way to get information about Java object heap allocations from the JVM that:

• Is low-overhead enough to be enabled by default continuously• Is accessible via a well-defined, programmatic interface• Can sample all allocations• Can be defined in an implementation-independent way (i.e., not limited to a particular GC algorithm

or VM implementation)• Can give information about both live and dead Java objects

• Transport Layer Security (TLS) 1.3• JEP 332 http://openjdk.java.net/jeps/332• Implementation of TLS 1.3 (RFC 8446) which provides significant security and performance

improvements over previous versions• Does not extend to Datagram Transport Layer Security (DTLS)

www.hujak.hr 61



JDK 12

• JDK 12 is currently in Early Draft Review• JSR 386 – usual suspects: Oracle, IBM, Red Hat, SAP, Azul…• openjdk.java.net/projects/jdk/12/

• Schedule:• 2018/05 Expert Group formation• 2018/07 Early Draft Review• 2018/10 - 2018/11 Public Review• 2019/01 - 2019/02 Proposed Final Draft• 2019/03 Final Release

• JEPs targeted to JDK 12, so far:• Switch Expressions (JEP 325)• Raw String Literals (JEP 326)

www.hujak.hr 62


More Long-term Future

• Project Amber – incubator for smaller, productivity-oriented language featuresand simplifying syntax• Local variable type inference, local variable syntax for lambdas, lambda leftovers, raw string

literals, pattern matching, switch expressions…

• Project Valhalla – incubator project for advanced JVM and language feature candidates• Value types and specialized generics

• Project Panama – to interconnect JVM and native code• Foreign function interface (FFI) replacement for JNI

• Project Loom – to reduce complexity in writing concurrent applications• Fibres (JVM-level threads) and continuations

• Project Metropolis – JVM re-written in Java, i.e. "Java on Java"• Using Graal experience, easier porting, performance to be explored (AOT compiler)

www.hujak.hr 63

Project Amber

• Project Amber includes:• Local variable type inference (JEP 286) – delivered in JDK 10• Local variable syntax for lambda parameters (JEP 323) – delivered in JDK 11• Switch Expressions (JEP 325) – expressions in switch statements (lambdas) –

planned for JDK 12• Raw string literals (JEP 326) – use of single backquote – planned for JDK 12• Lambda leftovers (JEP 302) – underscore for unused parameters – in progress• Pattern matching (JEP 305) – switch statement with case for different types of

objects – in progress• Enhanced Enums (JEP 301) – generic enums with type parameters – currently on

hold

• More at openjdk.java.net/projects/amber/

www.hujak.hr 64

http://openjdk.java.net/projects/amber/

Raw string literals (JEP 326) – examples

Runtime.getRuntime().exec("\"C:\\Program Files\\foo\" bar");

System.out.println("this".matches("\\w\\w\\w\\w"));

String html = "<html>\n" +

" <body>\n" +

" <p>Hello World.</p>\n" +

" </body>\n" +

"</html>\n";

Runtime.getRuntime().exec(`"C:\Program Files\foo" bar`);

System.out.println("this".matches(`\w\w\w\w`));

String html =

`<html>

<body>

<p>Hello World.</p>

</body>

</html>

`;

www.hujak.hr 65

Pattern matching (JEP 305) – example

String formatted;switch (obj) {

case Integer i: formatted = String.format("int %d", i); break;

case Long l: formatted = String.format("long %d", l); break;

case Double d: formatted = String.format(“double %f", d); break;

case String s: formatted = String.format("String %s", s); break

default: formatted = obj.toString();

}

www.hujak.hr 66

Switch Expressions (JEP 325) – example

int numLetters;switch (day) {

case MONDAY:case FRIDAY:case SUNDAY:

numLetters = 6;break;

case TUESDAY:numLetters = 7;break;

case THURSDAY:case SATURDAY:

numLetters = 8;break;

case WEDNESDAY:numLetters = 9;break;

default:throw new IllegalStateException("Hmm: " + day);

};

int numLetters = switch (day) {case MONDAY, FRIDAY, SUNDAY -> 6;case TUESDAY -> 7;case THURSDAY, SATURDAY -> 8;case WEDNESDAY -> 9;default -> throw new

IllegalStateException("Hmm: " + day);

};

www.hujak.hr 67

Project Valhalla

• Incubator project for advanced Java VM and language feature candidates

• Problem:• Java uses primitives for performance and objects for OO, encapsulation, polymorphism,

inheritance• But no ArrayList<int> • If we use Integer than (un)boxing, creation of object, heap, indirection reference…

• Value Objects (JEP 169) – "codes like a class, works like a primitive"• Supports methods, fields, implements interface, encapsulation, generic…• Doesn't support mutation or sub-classes

• Generics over Primitive Types (JEP 218) – extends generic types to support the specialization of generic classes and interfaces over primitive types

• More at openjdk.java.net/projects/valhalla/

www.hujak.hr 68

http://openjdk.java.net/projects/valhalla/

Project Panama and Project Loom

• Project Panama – interconnecting JVM and native code• Featuring native function calling from the JVM and native data access from the JVM• Foreign function interface (FFI) replacement for JNI• More at http://openjdk.java.net/projects/panama/

• Project Loom – reducing complexity in writing concurrent applications• Alternative, user-mode thread implementations, delimited continuations, and

other constructs involving call-stack manipulation• Proposal for lightweight fibres (JVM-level threads) as alternative implementation of

threads, managed by schedulers like ForkJoinPool, written in Java• Java programming model of ordinary Java threads would be preserved while

performance is improved and the footprint reduced• Less memory and almost zero overhead when task switching• More at http://openjdk.java.net/projects/loom/

www.hujak.hr 69

http://openjdk.java.net/projects/panama/

http://openjdk.java.net/projects/loom/

Backwards Compatibility

• It will be respected ☺

• But with no guarantees

• New version may include breaking changes

• Anything for removal will be deprecated first• Minimum of one release warning (6+ months)

www.hujak.hr 70

Container Awareness and Java Jakarta EE

• JVM more Docker container aware• Uses container CPU count and memory size

• Open sourcing Java EE• Jakarta EE as a part of Eclipse Foundation

• jakarta.ee/ – The New Home of Cloud Native Java

• Jakarta EE Developer Survey 2018, Eclipse Foundation• jakarta.ee/news/2018/04/24/jakarta-ee-community-survey/

• Current status• blogs.eclipse.org/post/mike-milinkovich/jakarta-ee-status-%E2%80%93-september-2018-update

www.hujak.hr 71

https://jakarta.ee/

https://jakarta.ee/news/2018/04/24/jakarta-ee-community-survey/

https://blogs.eclipse.org/post/mike-milinkovich/jakarta-ee-status-%E2%80%93-september-2018-update

Is Java really "Moving Forward Faster"?

• Well… yeah ☺

• Much more frequent Java releases

• Faster access to new features

• Many new improvement ideas

• A lot of maintenance and housekeeping

• Java remains free

• BTW, what about JavaOne?

www.hujak.hr 72

No more "JavaOne"?

• In 2018 JavaOne is larger than ever

• However, it goes by a new name…

• Oracle Code One –a conference for all developers• October 22-25, San Francisco• Usual prices $1400-$2000

• Keynotes:• www.oracle.com/code-one/keynotes.html

• On Demand Streaming:• www.oracle.com/code-one/on-demand.html

• 11 tracks:• Core Java Platform• Java Server-Side Development and

Microservices• Java Ecosystem• Containers, Serverless, and Cloud• Emerging Technologies• Modern Web• Development Tools• DevOps and Pipelines• Developer Community• Database, Big Data, and Data Science• MySQL

www.hujak.hr 73

http://www.oracle.com/code-one/keynotes.html

http://www.oracle.com/code-one/on-demand.html

Back to Croatian Reality

• But before that – one nice link: https://snyk.io/blog/jvm-ecosystem-report-2018

www.hujak.hr 74

https://snyk.io/blog/jvm-ecosystem-report-2018

A few nice things in 2017/2018…

• Java Zagreb meetups – many great meetups so far

• Java in high schools initiative• Together with Oracle Academy

• Croatian Makers league continues• Micro:bit, Logo, mBot, Scratch, Arduino, Little Bits…

• Program Digitalna akademija• ScratchJr, RunMarco, Studio Code, Play Lab, Scratch i App studio,

micro:bit, Arduino…

• Code Club Croatia and udruga Programerko

• Udruga za darovitu djecu "Dar"

• Great Javantura and JavaCro conferenceswww.hujak.hr 75

Where to study IT in Croatia?

• Java at Universities• Java is #1 for decades!!! ☺

• Where to study computing / computer science / information technology?• 15+ cities: Čakovec, Dubrovnik, Krapina, Križevci, Osijek, Pula, Rijeka, Sisak, Split,

Šibenik, Varaždin, Velika Gorica, Zabok, Zagreb, Zaprešić• 33+ educational organizations, including:

• 6 public universities• 13 private high schools

• 80+ educational programs• Undergraduate (3-4 years)• Graduate (1-2 years)• Professional• Postgraduate

www.hujak.hr 76

Javantura conference

• One Saturday in February

• 26 sessions

• 300 attendees

• Tickets with 50% discount for students

Looking forward to Javantura v6

on February 23rd, 2019in Zagreb☺

www.hujak.hr 77

Conferences HUJAK supports

www.hujak.hr 78

Calendar of Java-relates Conferences in EU

• Available at: hujak.hr/kalendar/

• If we are missing some please send email to info (at) hujak.hr

• Another great conference list at www.baeldung.com/java-conferences-europe

www.hujak.hr 79

https://hujak.hr/kalendar/

http://www.baeldung.com/java-conferences-europe

45+ company members

www.hujak.hr 80

Partners & Friends

www.hujak.hr 81

Thank you & greetings from HUJAK!

• Web page hujak.hr• www.hujak.hr

• LinkedIn group HUJAK• www.linkedin.com/groups?gid=4320174

• Facebook group page HUJAK.hr• www.facebook.com/HUJAK.hr

• Twitter profile @HUJAK_hr• twitter.com/HUJAK_hr

www.hujak.hr 82

above and beyond java 9, 10, 11, 12… - hroug...java-related conferences in croatia 6 conference...

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